Green seed coat colour retention in lentil (lens culinaris)

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Poor seed coat colour desirability in green lentil (Lens culinaris) costs lentil producers millions of dollars each year. The monetary value that Canadian lentil producers receive for their crop is based on the visual characteristics of the seed coat, mainly the colour. Higher value is given for samples described to have more desirable green seed coat colour. A breeding line, 1294M-23, has been noticed to consistently produce more desirable green lentil samples.A cross was made between 1294M-23 and a less desirable breeding line 1048-8R with the goal of studying the heritability of green seed coat desirability measured by the Acurum® machine. The resulting progeny were taken to F7 by single seed descent. In 2005 and 2006 the recombinant inbred lines (RILs) were seeded in a randomized complete block design at three sites in the current main lentil growing region of Saskatchewan. To measure the seed coat colour of the samples, the Acurum® machine, which is a colour analyzing machine developed for grain crops, was used to consistently compare the samples. The study illustrated that the trait has large environmental effects and is quantitative with a high broad sense heritability of 0.82, using this specific cross and environments. Transgressive segregation occurred for RILs that had more desirable green seed coats and lower index scores than the desirable parent, 1294M-23. A tester that included all registered green lentil cultivars set was grown with the RILs in all environments. The seed coat colour index scores of the tester set fit into a small section of the range of index scores. They all had relatively high mean index scores, meaning less desirable, showing little genetic variation for the trait in current Canadian green lentil cultivars. Chlorophyll was extracted from seed coats of some of the RILs. The amount of total chlorophyll, chlorophyll a, and chlorophyll b was compared to the Acurum® scores using regression analysis. The study found that there was significant relationship between chlorophyll a and b content and the index score, explaining 32 and 37 percent of the variation, respectively. Another portion of the study was to determine if preharvest treatment of the green lentil crop has an effect on the green seed coat colour of the sample. A set of genotypes consisting of all registered green seed coat cultivars was grown at two locations in Saskatchewan in both 2005 and 2006. Prior to harvest a plot of each genotype was swathed, and a second plot was desiccated with diquat. After harvest the samples were analyzed for green seed coat colour using the Acurum® machine. In general, across most genotypes, sites, and years, swathing produced a significantly more desirable green lentil sample. The desirable green parent from the RILs, 1294M-23 produced the most desirable green lentil sample in this study. When the maturity rating was correlated to the Acurum® score a significant positive relationship was found in 2005 but not in 2006. This showed that lines with later maturity could be associated with more desirable green seed coat colour in some environments. Thus caution must be taken when selecting for more desirable phenotypes that genetic gains are being made rather than indirect selection for longer maturity.